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<h1>Neck</h1>

<h2>Laminated Construction</h2>

<p>If the neck blank is not perfectly quartersawn, layering it is a good idea. The grain lines should form a V shape, this keeps them as long as possible &mdash; which is good for stability.</p>

<p>Strips of ebony have been used traditionally to reinforce the neck. Layers of carbon fibers are currently getting increased popularity, although the workflow is somewhat more complicated. Additionally, you don't want the fibers to protrude though the surface, which makes the matter even more complicated.</p>

<p>Besides the constructional purpose, there is also a nice visual effect. </p>

<p>Extending the stripes through the heel can become complicated</p>

<h2>Truss Rod Or No Truss Rod?</h2>

<p>According to Cumpiano in one of his newsletters, a trussrod on a classical guitar does not make much sense, because the string tension is rather low, compared to steel-string acoustic and electric guitars. </p>

<p>However, a 3/4" (20 mm) square steel tube, about 12" (305 mm) long  (Middleton and Cumpiano), firmly glued with epoxy on all surfaces, helps to keep the neck straight.  Its position is more to the nut, not centered between 12th and 1st fret. Additionally, an increased mass in the neck tends to produce a brighter sound. Reportedly, there is a builder (Kasha?) that put lead in the neck, and counterbalanced it with a lead fill-in in the tailpiece. </p>

<p>The "more neck mass, better sound" theory can be verified easily by clamping a mass on the headstock. The guitar immediately becomes louder and brighter. When removed, the effect disappears.</p>

<p>Other makers incorporate layers of carbon fibers into the neck to counterbalance string tension.</p>

<p>The completed neck/finger assembly, in my opinion, <em>can</em> be a source of deflection. Wood <em>does</em> have a longitudinal shrinkeage factor, although it is much smaller than the cross grain shrinkeage factor. And of course, this factors depend to a great deal on the wood species, as well as on the individual pieces at hand. </p>

<p><a href="http://www.cordobaguitars.com/article.php?articleid=6">Cordoba Guitars</a> for example, build their classicals and flamencos with a two-action truss rod.</p>

<p>This makes an adjustable truss rod worth thinking about.</p>

<h2>Pre-Loading the Neck</h2>

<p>In the workshop where Cumpiano was taught they glued the fretboard with white glue, and kept the underside of the neck wet, while the fretboard was clamped down with a massive caul. The humidity expands the neck to a small degree, while forced flat while the glue cured. After that, the neck shrunk back due to drying, which caused a slight back-bow of the neck in the order of the effect caused by string tension.</p>

<p>When the neck/fretboard had set, the fretboard was planed straight, so that the string tension could create the desired neck relief that prevented string buzz.</p>

<p>A similar technique can be used with a single action truss rod: The installation is done with a certain front bow, caused by preloading. After assembly, the truss rod is fastened a little bit to compensate that front bow. Now if the neck responds to a high humidity conditions and produces a back bow, the truss rod can be released a little bit to compensate that.</p>

<p>With a two-way truss rod, preloading is not necessary. LMI and other supplier has them.</p>

<p><a href="<https://www.youtube.com/watch?feature=player_embedded&v=tLY3iN1Atn4">Here</a> video that illustrates the installation.</p>

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